the odds on iem, according to its proprietor, joyce berg? >> right now, the markets are favoring obama. if you look at the winner-take- all market, that market is showing that our traders believe there's an 80% chance obama will get more than 50% of the popular vote. >> reporter: that was before the first presidential debate, however. the odds are now much lower. but they're still above 60% that president obama will win the popular vote. so, who's right, the professors, the pollsters, or the plungers? lets start with economics professor ray fair. fair's equation uses just four variables to figure each candidates odds: incumbency-- a sitting president has an edge; party-- being a republican seems to help; inflation rate-- the lower the better; rate of income growth per person-- the higher the better. so, this year? >> the model says its a very close election predicted. if the economy were booming, the equation would be predicting a pretty substantial obama victory. if the economy were going into a recession, it would be a substantial romney v